If mutter is going to be a "real" library, then it should install its
includes so that users can do
#include <meta/display.h>
rather than
#include <display.h>
So rename the includedir accordingly, move src/include to src/meta,
and fix up all internal references.
There were a handful of header files in src/include that were not
installed; this appears to have been part of a plan to keep core/,
ui/, and compositor/ from looking at each others' private includes,
but that wasn't really working anyway. So move all non-installed
headers back into core/ or ui/.
https://bugzilla.gnome.org/show_bug.cgi?id=643959
Cleanly build with --warn-fatal. Implementation:
* Liberally apply (skip) where the API is clearly C only, e.g. uses
XLib. The theming code and MutterPlugin are skipped too.
* Add missing (transfer) and (element-type) annotations
For a few functions that had a comment, I turned it into gtk-doc, but
I didn't (with a few exceptions) try to write new documentation in
this pass.
